A typical vehicle is manufactured with a plurality of openable doors. Each door is typically mounted on hinges within a door opening. Some larger vehicles have sliding doors that slide from an open position to closed position thus, egress and ingress of the vehicle is possible without requiring a large open area beside the vehicle to allow for pivoting of the door. This is particularly useful in parking lots where the area between the vehicles is typically not large enough to allow for full pivoting of the opening doors. Moreover, such sliding doors also allow the vehicles to have larger door openings.
Accordingly, sliding doors provide access to large door openings without requiring a large area adjacent to the vehicle which would be required for a door that pivots on its hinge. In one configuration, a power sliding door is supported and guided by an upper track, a center track and a lower track. An upper roller is attached to the power sliding door and travels in the upper track. A lower roller is attached to a lower portion of the sliding door and runs or travels in the lower track. A hinge and roller assembly is pivotally attached to a rear portion (e.g., towards the rear of the vehicle) of the door between the upper and lower portions of the door. The hinge and roller assembly is also received in the track to allow for sliding or movement of the door.
In addition to the usage of sliding doors in vehicles, power drive systems have been implemented wherein automatic opening, closing, locking and unlocking of the sliding door is facilitated through a drive system coupled to the sliding door. Presently, some sliding doors are driven through cables attached to the forward and aft sides of the center roller hinge (e.g., a hinge mounted towards the center of the door with respect to the upper and lower edges of the same). During installation on the vehicle, the cables are separately routed into the interior of the vehicle housing (e.g., between the inner and outer surfaces of the vehicle body) through holes in the sheet metal and are wrapped around pulleys of the power sliding door drive unit within the vehicle. These systems are complex, non-modular, cumbersome to install, and require the cables to be routed through the vehicle, the system, tensioned and then secured to the hinge during assembly of the system on the vehicle (e.g., on the assembly line).
The drive unit output force necessary to seal the door with the front cable attached to the center roller hinge is larger than the door seal force (e.g., the necessary seal force applied normal to the surface of the door or inwardly towards the vehicle from the exterior of the door). The aforementioned seal force refers to the force necessary to close the door when it is positioned over or about the door opening into which the door is received. The previously mentioned difference in required seal force is typically due to the inefficiency of transferring the force from the cable to the door via the center roller hinge/roller track/door interface.
In addition, non-modular power drive systems include many components that must be installed together on the assembly line. Accordingly, many power sliding doors and their associated non-modular drive systems require significant work to install on the assembly line as multiple separate components must be installed and tested during the vehicle assembly process. Moreover, the configuration of these systems effect the efficiency of the motor drive unit thereby requiring additional power to close the vehicle door as it slides in the guide tracks.
Accordingly, it is desirable to provide a power drive system for a vehicle sliding door that is efficient in transferring force to the sliding door and is easy to install. Moreover, it is desirable to provide a system that does not take up a large amount of space within the vehicle.